Scientists observed mysterious motions within a solar flare in 1999. This flare has bright energy erupting outwards from the Sun. It solar flare also displayed a downward flow of motion. This looks like as if material was falling back towards the Sun. Scientists have described it as “downward-moving dark voids”. Scientists wanted to find out what they are seeing.
The study has been published in Nature Astronomy. Center for Astrophysics, Harvard & Smithsonian offered a new explanation for the poorly understood downflows. They have referred it as supra-arcade downflows.
Scientists thought that SADs are tied to magnetic reconnection since their discovery in the 90s. The process happened when magnetic fields break. This released fast moving and extremely energetic radiation. Then it reformed.
Scientists thought the dark downflows were signs of the broken magnetic fields “snapping back” to the Sun after a solar flare eruption. Most of the downflows observed by scientists are “puzzlingly slow”.
Scientists analysed downflow images captured by the Atmospheric Imaging Assembly (AIA) onboard NASA’s Solar Dynamics Observatory. It was designed and built partially at the CfA and led by the Lockheed Martin Solar Astrophysics Laboratory. The AIA takes images of the Sun every twelve seconds in seven different wavelengths of light. It measures variations in the Sun’s atmosphere.
Scientists made 3D simulations of solar flares and compared them to the observations.
They found out most SADs are not generated by magnetic reconnection. They form on their own in the turbulent environment. They are the result of two fluids with different densities interacting.
Scientists are seeing the same thing that happens when water and oil are mixed together. Two different fluid densities are unstable and ultimately separate. Scientists continue studying SADs and other solar phenomenon using 3D simulations.
They want to better understand magnetic reconnection. Scientists will understand the process that drive solar flares and eruptions from the Sun. This will help in develop tools to forecast space weather and reduce its impacts.